1. Field of the Invention
The present invention relates to a power conversion apparatus.
2. Description of the Related Art
In a power conversion apparatus inputting and outputting three-phase alternating-current power, a minimum configuration of a conversion circuit for one phase (hereinbelow referred to as a module of conversion circuit) includes a half-bridge circuit including two semiconductor switches and diodes connected in parallel with the respective semiconductor switches, a capacitor connected between a positive electrode side and a negative electrode side, a conductor wire electrically connecting these parts, and a gate driving circuit. The gate driving circuit is a circuit turning on/off the semiconductor switches in response to a signal from a control circuit on top of a system.
Meanwhile, a capacity increase of the power conversion apparatus can be achieved by connecting in parallel as many modules of conversion circuit as necessary and using a circuit combining output terminals of the half-bridge circuits as the conversion circuit for one phase. In the case in which the plurality of modules of conversion circuit are used, disconnection (detachment) of the aforementioned parallel connection and connection are desirably simple from a viewpoint of efficiency of maintenance.
On the other hand, in a case of connecting the conversion circuit including the capacitor to a power supply, when the amount of charging current to the uncharged capacitor is excessive, heat is generated at a capacitor terminal, portion significantly. In relation to this, a rectifier including a capacitor inrush current prevention circuit is known (for example, refer to JP-5-284748-A.)